The Caprellidea (Crustacea: Amphipoda) from Tasmania

Transcription

1 JOURNAL OF NATURAL HISTORY 20 APRIL 2004, 38, The Caprellidea (Crustacea: Amphipoda) from Tasmania J. M. GUERRA-GARCÍA and I. TAKEUCHI Laboratorio de Biología Marina, Departamento de Fisiología y Biología Animal, Facultad de Biología, Universidad de Sevilla, Apdo. 1095, Sevilla, Spain; jmguerra@us.es Departament of Life Environment Conservation, Faculty of Agriculture, Ehime University, Tarumi, Matsuyama, Ehime , Japan; takeuchi@agr.ehime-u.ac.jp (Accepted 9 October 2002) The taxonomy of the Caprellidea from the Tasmanian coast is reviewed with data on species composition and biogeographical characteristics. Four new species, Caprella edgari n. sp., Hircella inermis n. sp., Orthoprotella tuberculata n. sp. and Paraproto tasmaniensis n. sp. are described, and detailed descriptions of Caprella acanthogaster Mayer, 1890, Orthoprotella tasmaniensis Guiler, 1954 and Paraproto spinosa (Haswell, 1885) are provided. Lateral view figures of the 18 species found in Tasmanian waters until now, with a key to species level, are also given. The species diversity of littoral caprellids from Tasmania is considerably high when compared with other regions of similar latitude in the southern hemisphere, probably due to the warm effect of the East Australian current passing down towards the east coast of Tasmania. This fact, with previous studies on the low concentrations of dissolved nutrients in rivers and dark tannin-stained waters on the west coast, could result in species richness and abundance being clearly higher on the east coast of Tasmania. KEYWORDS: Amphipoda, Caprellidea, Tasmania, new taxa, taxonomy, biogeography. Introduction The Caprellidea, one of the four suborders of Amphipoda, are considered to constitute a keystone part of shallow-water marine ecosystems as secondary and tertiary producers. They usually live as epibionts on a variety of substrata from the littoral zone to a depth of 4790 m (e.g. McCain, 1968; Laubitz, 1970, 1972; Laubitz and Mills, 1972; Arimoto, 1976; Takeuchi, 1999) and many are commensal with other invertebrates such as echinoderms, hydroids and bryozoans (see Guerra- García, 2001a). If Australia s interesting and unique biota can be said to result from the remote geographical position and insularity of Australia, this feature is further heightened Journal of Natural History ISSN print/issn online 2004 Taylor & Francis Ltd DOI: /

2 968 J. M. Guerra-García and I. Takeuchi in Tasmania, being the most remote and isolated part. Despite interesting characteristics, the invertebrate fauna of Tasmania is so far poorly known. In particular, the Caprellidea from this region have been scarcely investigated. The first study on the Caprellidea from Tasmania was carried out by Briggs (1914), who reported only three species, followed by Guiler (1954), who listed 10 species, including the description of seven new species, based on collections from the Gordon Area and the east coast. Since the descriptions and drawings of Guiler (1954) are not sufficient for modern taxonomy, the validity of some of these taxa is questionable. This leads to necessary redescriptions of species established by Guiler (1954), as well as a review of the Caprellidea from Tasmania. In the past two decades, however, studies on the Amphipoda of Tasmanian coasts have been focused mainly on ecology, especially phytal community structures ( Edgar, 1983, 1991) and the taxonomy of the Gammaridea inhabiting the algal community (Moore, 1981, 1987, 1989). No taxonomic studies have been carried out on Caprellidea from Tasmania since the study of Guiler (1954). Dr G. Edgar collected quantitative samples of Tasmanian caprellids during which were deposited in the collections of the Australian Museum, Sydney. In 1991, the Australian Museum s staff collected material from several stations along the east and west coasts of Tasmania, as a part of a general programme to study the marine invertebrates from Tasmanian waters. In 1996, one of the authors, I.T., with G. Edgar, made some collections in Tasmania concentrating on the Caprellidea, to assemble good specimens for descriptions. It is useful to collect by targeting specimens suitable for description and to avoid damaging the specimens, which can make them useless for taxonomic descriptions. The material identified by E. R. Guiler has also been examined, as far as it was available, in the present paper. As a result of the study of the new collections and of Guiler s materials, 18 valid species of caprellids were identified, with four being new to science. Thus, the present paper deals with the descriptions of four new species, redescriptions of four poorly known species and the elaboration of a key based on figures in lateral view of all species, which can also be useful for future biological studies dealing with the Caprellidea from Tasmania. The studied material is deposited in the Australian Museum (AM) and the Tasmanian Museum and Art Gallery (TM). List of stations The following list of stations includes the exact sampling locality, depth, collector(s) and date. Data for substrata were also included where available. A map of the study area is shown in figure 1. P 48754: Armstrong Channel, Cape Barren Island, S, E, 5 m, G. Edgar, 16 June P 48755: Curtis Island, S, E, 5 m, G. Edgar, 17 June P 48756: Cape Portland, S, E, Sargassum, 1 m, G. Edgar, 11 January P 48757: Judgement Rocks, S, E, 5 m, G. Edgar, 22 June P 48758: Landing Beach, Hogan Island, S, E, 5 m, G. Edgar, 18 June P 48759: Fancy Point, S, E, Sargassum, 2 m, G. Edgar, 4 August P 48760: Fancy Point, S, E, algae, 2 m, G. Edgar, 11 November P : Tinderbox, S, E, Caulerpa, 3 m, G. Edgar, 10 May 1978.

3 The Caprellidea from Tasmania 969 Bass Strait TASMANIA km E 44 S FIG. 1. Map of Tasmania showing the sampling localities. P 48763: Jacobs Boat Harbour, S, E, Zonaria, 5 m, G. Edgar, 28 November P 48764: Jacobs Boat Harbour, S, E, 30 m, G. Edgar, 28 November P 48765: Sarah Island, Bathurst Channel, S, E, 8 m, G. Edgar, 16 February P 48766: Point, Bruny Island, S, E, Sargassum, 8 m, G. Edgar, 29 October P 48767: Breaksea Island, Port Davey, S, E, 8 m, G. Edgar, 16 February P 48768: Breaksea Island, Port Davey, S, E, 4 m, G. Edgar, 29 November P : Breaksea Island, Port Davey, S, E, 1 m, G. Edgar, 16 February P 48774: Green Bluff, S, E, 5 m, G. Edgar, 28 June P : Whalers Cove, S, E, 5 m, G. Edgar, 30 June P 48777: Pointed Cliffs, Maria Island, S, E, 4 m, G. Edgar, 27 June P : Jacobs Boat Harbour, S, E, algae, 1 m, G. Edgar, 5 February P 48784: Governor Island, Bicheno, S, E, Lessonia holdfast and bryozoa, 10 m, G. Edgar, 20 May P 48785: Mercury Passage, S, E,? m, G. Edgar, 3 June 1993.

4 970 J. M. Guerra-García and I. Takeuchi P 48786: Franklin Sound, S, E, red algae, 10 m, G. Edgar, 6 January P : Scallop aquaculture, Mercury Passage, S, E, Undaria pinnatifida, 5 m, G. Edgar and N. Barrett, 29 March P : Ile de Nord, Maria Island, Mercury Passage, S, E, red algae Plocamium dilatatum and P. angustum, 11 m, I. Takeuchi and G. Edgar, 29 March P 48794: Ile de Nord, Maria Island, Mercury Passage, S, E, brown algae Phyllospora comosa, 4 m, I. Takeuchi and G. Edgar, 29 March P 48795: near Garden Island Point, D Entrecasteaux Channel, S, E, brown hydroid, 5 m, I. Takeuchi and G. Edgar, 31 March P 48796: near Garden Island Point, D Entrecasteaux Channel, S, E, brown algae Acrocarpia paniculata, 5 m, I. Takeuchi and G. Edgar, 31 March P 48797: near Garden Island Point, D Entrecasteaux Channel, S, E, red algae Jeannerettia lobata, 10 m, I. Takeuchi and G. Edgar, 31 March P : Cemetery Bluff, Adventure Bay, Bruny Island, S, E, brown algae Perithalia caudata, 4.5 m, I. Takeuchi and G. Edgar, 4 April P 48801: Cemetery Bluff, Adventure Bay, Bruny Island, S, E, bryo zoans Perithalia caudata, 4.5 m, I. Takeuchi and G. Edgar, 4 April P 48802: Cemetery Bluff, Adventure Bay, Bruny Island, S, E, brown algae Zonaria cf turneriana, 4.5 m, I. Takeuchi and G. Edgar, 4 April P : Cemetery Bluff, Adventure Bay, Bruny Island, S, E, brown algae Sargassum vestitum, 3 m, I. Takeuchi and G. Edgar, 4 April P 48806: Cemetery Bluff, Adventure Bay, Bruny Island, S, E, red alga Callophyllis lambertii, 5 m, I. Takeuchi and G. Edgar, 4 April P : Cemetery Bluff, Adventure Bay, Bruny Island, S, E, brown algae Sargassum vestitum and Acrocarpia paniculata, 5 m, I. Takeuchi and G. Edgar, 4 April P : Cemetery Bluff, Adventure Bay, Bruny Island, S, E, red algae Plocamium angustum, 3 m, I. Takeuchi and G. Edgar, 4 April TAS-107: Clerk Point, Georges Bay, S, E, sea grass (Heterozostera tasmania), dip net, 0.5 m, P. B. Berents and R. T. Springthorpe, 12 April TAS-113: St Helens Rocks, S, E, Ecklonia holdfasts, 10 m, R. T. Springthorpe and C. J. McCormick, 13 April TAS-114: St Helens Rocks, S, E, bryozoan?vittaticella, 10m, R. T. Springthorpe and C. J. McCormick, 13 April TAS-115: St Helens Rocks, S, E, bryozoan?orthoscuticella, 15 m, R. T. Springthorpe and C. J. McCormick, 13 April TAS-121: St Helens Rocks, S, E, mixed algae and bryozoans, 15 m, R. T. Springthorpe and C. J. McCormick, 13 April TAS-123: St Helens Rocks, S, E, encrusting sponges on rocks among Ecklonia and Cystophora kelp, 10 m, R. T. Springthorpe and C. J. McCormick, 13 April 1991.

5 The Caprellidea from Tasmania 971 TAS-129: Elephant Rock north of St Helens Point, S, E, Caulerpa, 20 m, R. T. Springthorpe and C. J. McCormick, 14 April TAS-132: Elephant Rock north of St Helens Point, S, E, red algae, 20 m, R. T. Springthorpe and C. J. McCormick, 14 April TAS-133: Elephant Rock north of St Helens Point, S, E, Ulva, corallines,?austromegabalanus, Pyura, intertidal swash zone, P. B. Berents, 14 April TAS-136: Elephant Rock north of St Helens Point, S, E, sponges on rocky substrate, 20 m, R. T. Springthorpe and C. J. McCormick, 14 April TAS-151: Sloop Reef, Bay of Fires, S, E, red alga, rocky bottom, 23 m, R. T. Springthorpe and C. J. McCormick, 15 April TAS-152: Sloop Reef, Bay of Fires, S, E, yellow finger sponge and bryozoan (Iodictyum sp. id: P. S. R. Nair), rocky bottom, 23 m, R. T. Springthorpe and C. J. McCormick, 15 April TAS-153: Sloop Reef, Bay of Fires, S, E, sponges, rocky bottom, 23 m, R. T. Springthorpe and C. J. McCormick, 15 April TAS-179: North side of Esperance Point, D Entrecasteaux Channel, S, E, mixed red algae, sponges and Caulerpa, 14 m, S. J. Keable, J. K. Lowry and R. T. Springthorpe on the Flying Scud, 18 April TAS-180: North side of Esperance Point, D Entrecasteaux Channel, S, E, brown algae, 12 m, S. J. Keable, J. K. Lowry and R. T. Springthorpe on the Flying Scud, 18 April TAS-183: North side of Esperance Point, D Entrecasteaux Channel, S, E, sponges, 12 m, S. J. Keable, J. K. Lowry and R. T. Springthorpe on the Flying Scud, 18 April TAS-184: North side of Esperance Point, D Entrecasteaux Channel, S, E, mixed red algae, m, S. J Keable, J. K. Lowry and R. T. Springthorpe on the Flying Scud, 18 April TAS-214: North side of Scott Point, D Entrecasteaux Channel, S, E, red algae, 18 m, R. T. Springthorpe and P. M. Berents on the Flying Scud, 20 April TAS-218: North side of Scott Point, D Entrecasteaux Channel, S, E, flat red alga, 18 m, R. T. Springthorpe and P. M. Berents on the Flying Scud, 20 April TAS-289: Off Hannant s Bight, Cape Sorell, S, E, red algae with epiphytic algae, bryozoa and sponges, 16 m, R. T. Springthorpe and P. M. Berents on the Flying Scud, 27 April TAS-320: 100 m north of Fleurieu Point, Freycinet Peninsula, S, E, brown alga Caulocystis, 6 m, S. J. Keable and R. T. Springthorpe on the Flying Scud, 30 April TAS-330: Joes Bight, Freycinet Peninsular, S, E, sponges, m, R. T. Springthorpe and S. J. Keable, 1 May TAS-332: Joes Bight, Freycinet Peninsular, S, E, airlift from vertical rock face encrusted with a few small lace bryozoans and algal turf, 17 m, R. T. Springthorpe and S. J. Keable, 1 May TAS-333: Joes Bight, Freycinet Peninsular, S, E, airlift from sandy boulder suface, 17 m, R. T. Springthorpe and S. J. Keable, 1 May TAS-334: Joes Bight, Freycinet Peninsular, S, E, brown algae, 17 m, R. T. Springthorpe and S. J. Keable, 1 May 1991.

6 972 J. M. Guerra-García and I. Takeuchi TAS-348: Joes Bight, Freycinet Peninsula, S, E, filamentous brown algae, 17 m, R. T. Springthorpe and S. J. Keable, 1 May TAS-349: Joes Bight, Freycinet Peninsula, S, E, red algae, 17 m, R. T. Springthorpe and S. J. Keable, 1 May List of species Taking into account that the phylogeny and higher classification of the Caprellidea is still under debate, the genera have been grouped following Takeuchi (1993). Family Phtisicidae Vassilenko, 1968 Caprellina longicollis (Nicolet, 1849) (figure 2). Dodecas tasmaniensis Guiler, 1954 (figure 3). Hircella inermis new species (figures 4 8). Paraproto tasmaniensis new species (figures 9 14). Paraproto spinosa ( Haswell, 1885) (figures 15 21). Family Caprellidae Leach, 1814 Caprella acanthogaster Mayer, 1890 (figures 22 26). Caprella acanthopoda Guiler, 1954 (figure 27). Caprella danilevskii Czerniavksi, 1868 (figures 28, 29). Caprella edgari new species (figures 30 33). Caprella equilibra Say, 1818 (figure 34). Caprella penantis Leach, 1814 (figure 35). Caprella scaura Templeton, 1836 (figure 36). Metaprotella cf sandalensis Mayer, 1898 (figure 37). Noculacia sp. (figure 38). Orthoprotella gordoni Guiler, 1954 (figure 39). Orthoprotella tasmaniensis Guiler, 1954 (figures 40 44). Orthoprotella tuberculata new species (figures 45 51). Paracaprella alata Mayer, 1903 (figure 52). Systematics Complete synonymies and distribution records of the species can be found in McCain and Steinberg (1970). Herein, we have only included the most relevant references for each species. Family PHTISICIDAE Vassilenko, 1968 Caprellina longicollis (Nicolet, 1849) (figure 2) Caprella longicollis Nicolet, 1849: , pl. 4, figure 3. Caprella brevicollis Nicolet, 1849: , pl. 4, figure 4. Caprellina longicollis: Mayer, 1882: 27 28, figures 4, 5; Mayer, 1890: 15 16, pl. 6, figure 4; McCain, 1969: , figure 2. Material examined. P48755: one male; P48757: one male, one female; P48765: one female; P48769: one male; P48775: two females; P48778: one male; P48779: one female; P48781: one male; P48783: one female; TAS-107: seven males, one female; TAS-114: one male; TAS-115: one male, one female; TAS-121: three males; TAS-151: four males, four females.

7 The Caprellidea from Tasmania 973 FIG. 2. Caprellina longicollis (Nicolet, 1849). Lateral view. (A) Male; (B) female. Scale bar: 1 mm. Remarks. Caprellina longicollis was originally recorded from Chile (Nicolet, 1849), but the exact type locality was not cited. Caprellina longicollis has been recently redescribed based on specimens from Coquimbo, Chile by Guerra-García (2001b); specimens from Tasmania are in good agreement with the redescription. This species has also been found from South Africa, New Zealand, Snares Islands, Antipodes Islands and Auckland Islands (McCain, 1969; McCain and Steinberg,

8 974 J. M. Guerra-García and I. Takeuchi 1970); therefore, C. longicollis could probably be a cosmopolitan species around the cold-temperate region of the southern hemisphere. Dodecas tasmaniensis Guiler, 1954 (figure 3) Dodecas tasmaniensis Guiler, 1954: , figures Material examined. Type material (deposited in the Tasmanian Museum and Art Gallery): holotype female (G53) and allotype male (G54), Mt Creek Gordon, Tasmania, Material newly collected: P48755: four males, four females, nine juveniles; P48761: two males, two females, two juveniles; P48762: one male; P48782: FIG. 3. Dodecas tasmaniensis Guiler, Lateral view. (A) Male; (B) female. Scale bar: 1 mm.

9 The Caprellidea from Tasmania 975 one female; TAS-115: many specimens; TAS-121: one male, one female: TAS-129: one male; TAS-132: one male; TAS-136: one male; TAS-152: one female; TAS-180: three males, five females, one juvenile; TAS-183: one female; TAS-184; six males, two females; TAS-218: two females; TAS-333: one male, one female. Remarks. The genus Dodecas, which is endemic to the southern hemisphere, comprised seven species of doubtful validity (Laubitz, 1991): D. decacentrum Stebbing, 1910, D. elongata Stebbing, 1883, D. eltaninae McCain and Gray, 1971, D. grandimanus Guiler, 1954, D. hexacentrum Mayer, 1903, D. reducta Barnard, 1932 and D. tasmaniensis Guiler, Guiler (1954) synonymized D. decacentrum with D. hexacentrum. McCain and Steinberg (1970) and Laubitz (1991) remarked that D. grandimanus and D. tasmaniensis appeared to be variants of D. hexacentrum. Laubitz (1991) considered that D. eltaninae and D. reducta were synonymous with D. elongata. Taking into consideration all these synonymies, the genus would comprise only two species, D. elongata and D. hexacentrum. Nevertheless, recently, after consulting the type material of D. hexacentrum and D. decacentrum deposited in the Australian Museum and material newly collected from New South Wales, Australia, one of the authors ( I.T.) considered that both D. hexacentrum and D. decacentrum should be treated as valid species. After examination of the types and additional material of D. tasmaniensis this species seems to be a junior synonym of D. decacentrum ( Takeuchi, in preparation). The type material of D. grandimanus (holotype female G55, Mt Creek Gordon, Tasmania, 1952) has also been consulted. It is in poor condition, and there are no other known specimens, but it is probably synonymous with D. decacentrum. Traditionally, Dodecas georgiana Schellenberg, 1931 had also been included in the genus Dodecas. However, Laubitz (1991) considered this species to belong to the genus Dodecasella. After checking the type material of this species, housed at the Swedish Museum of Natural History (NRM T-5772) and still labelled as Dodecas georgiana, we confirm the need to transfer definitively Dodecas georgiana to the genus Dodecasella, mainly on the basis of the absence of gills on pereonite 2. Hircella inermis new species (figures 4 8) Material examined. P48776: one male; P48804: three males; P48808: one male; P48815: four males, three females. Etymology. The specific name inermis was selected because the body of this species is completely smooth, differing from H. cornigera, the other species in the genus, which has dorsal projections. Type material. Holotype male P48776 (AM P48776), collected from Whalers Cove by G. Edgar, 30 June 1993, 5 m deep. Allotype female P48815 (AM P48815) collected from Cemetary Bluff by I. Takeuchi and G. Edgar, 4 April 1996, clinging on the red alga Plocamium angustum, 3 m deep. Paratypes (AM P61390): four males, two females P Type locality. Whalers Cove (43 17 S, E), Tasmania, Australia. Other records. Cemetary Bluff, Adventure Bay, Bruny Island (43 20 S, E), Tasmania, Australia. Description Holotype male Body length. 9.3 mm.

10 976 J. M. Guerra-García and I. Takeuchi FIG. 4. Hircella inermis new species. Lateral view. (A) Male; (B) female. Scale bar: 1 mm. Lateral view (figure 4A). Body dorsally smooth. Head rounded. Eyes small. Pereonite 1 fused with head, suture not present; pereonites 2 5 increasing in length; pereonites 5 and 6 subequal; pereonite 7 the shortest. Gills (figure 4A). Present on pereonites 2 4, oval, length about twice width. Gills on pereonite 4 slightly shorter than those on pereonites 2 and 3. Mouthparts. Upper lip (figure 5B) symmetrically bilobed, pubescent apically. Mandibles (figure 6A, B) with three-articulate palp; distal article of palp with setal formula and apical projection carrying a row of setulae; second article provided

11 The Caprellidea from Tasmania 977 FIG. 5. Hircella inermis new species. Male. (A) Maxilliped; (B) upper lip; (C) lower lip; (D) maxilla 1; (E) maxilla 2. Scale bars: 0.1 mm. with 11 simple setae; mandibular molar absent; left mandible with incisor fivetoothed, lacinia mobilis five-toothed followed by a row of minutely serrated plates decreasing in size; incisor of right mandible five-toothed, lacinia mobilis deeply serrate, followed by a row of minutely serrate plates; molar flake absent. Lower lip (figure 5C) with inner lobes well demarcated; inner and outer lobes provided with setulae on apical end. Maxilla 1 (figure 5D) outer lobe carrying five robust setae, serrate laterally; distal article of the palp with nine apical setae and a row of seven

12 978 J. M. Guerra-García and I. Takeuchi FIG. 6. Hircella inermis new species. Male. (A) Left mandible; (B) right mandible. Scale bar: 0.2 mm. setae medially. Maxilla 2 (figure 5E) inner lobe oval carrying 11 setae distally and a row of small setulae; outer lobe elongate, twice larger than inner lobe, with 13 apical setae. Maxilliped (figure 5A) inner plate rectangular carrying two spine-like setae distally; outer plate oval, as large as the inner plate, with two robust setae distally; palp four-articulate, dactylus without rows of setulae. Antennae. Antenna 1 (figure 7A) robust, about one-third of body length; flagellum eight-articulate. Antenna 2 (figure 7B) about one-third of antenna 1; swimming setae absent; flagellum three-articulate.

13 The Caprellidea from Tasmania 979 FIG. 7. Hircella inermis new species. (A D) Male. (A) Antenna 1; (B) antenna 2; (C) gnathopod 1; (D) gnathopod 2. (E) female gnathopod 2. Scale bars: (A, D) 1 mm; (B,C,E)0.5mm.

14 980 J. M. Guerra-García and I. Takeuchi FIG. 8. Hircella inermis new species. (A) Female pereopod 5; (B) male pereopod 6; (C) male pereopod 7; (D) male abdomen (ventral view); (E) male abdomen (lateral view); (F) female abdomen (ventral view). Scale bars: (A) 0.05 mm; (B, C) 1 mm; (D F) 0.3 mm. Gnathopods. Gnathopod 1 (figure 7C) as long as ischium, merus and carpus combined; propodus oval, length about 1.3 times width, palm with a row of minute setulae proximally, two pairs of proximal grasping spines and two rows of short spines along the palm; grasping margin of propodus palm and dactylus smooth.

15 The Caprellidea from Tasmania 981 Gnathopod 2 (figure 7D) inserted on the anterior half of pereonite 2; basis as long as pereonite 2; ischium rectangular; merus rounded; carpus short and triangular; propodus rectangular, about 1.2 times as long as the basis; palm provided with six grasping spines proximally and a distal projection; dactylus thickened medially. Pereopods. Pereopod 5 absent in male. Pereopods 5 and 6 (figure 8B, C) robust; basis without carina, ischium short and rectangular; ischium about 1.8 times as long as merus; propodus as long as ischium and merus combined, palm carrying three (pereopod 6) and four (pereopod 7) pairs of robust denticulate setae proximally and a row of smaller ones along the grasping margin. Penes (figure 8D). Penes situated laterally, length about 1.2 times width. Abdomen (figure 8D, E). Abdomen with a pair of tiny projections, short and setose (probably rudimentary pleopods), two pairs of long appendages (uropods) and a single dorsal lobe (figure 8E); first pair of appendages two-articulate, distal article about one-third as long as proximal one; second pair slightly shorter than the first pair, being one-articulate. Allotype female Body length 7.1 mm. Flagellum of antenna 1 with five articles (figure 4B). Propodus palm of gnathopod 2 (figure 7E) without distal projection; dactylus not thickened medially. Oostegites not setose (figure 4B). Pereopod 5 present but extremely reduced (about 50 mm), smooth and triangular, about three times as long as wide. Abdomen (figure 7F) with the pleopods reduced to a tiny plate. Remarks The only other species of Hircella known so far is Hircella cornigera described by Haswell (1880) as Caprella cornigera, collected from Port Jackson, New South Wales. Mayer (1882) established the genus Hircella mainly on the basis of the absence of pereopod 5. The genus Liriarchus Mayer, 1912 is also characterized by the absence of pereopod 5 in males, or extremely reduced in females. However, Hircella and Liriarchus can be differentiated by the abdomen: there are two pairs of appendages in Hircella and only one pair in Liriarchus. This enabled the present specimens collected from Tasmania to be assigned to the genus Hircella on the basis of the presence of two pairs of appendages on the abdomen. Although the type material of Hircella cornigera is lost (Springthorpe and Lowry, 1994), the specimens of H. inermis n. sp. have been compared with material of H. cornigera newly collected from New South Wales. Hircella inermis can be differentiated from H. cornigera mainly on the basis of the following characteristics: (1) pereopod 5 is present in females of H. inermis (although very reduced) and absent in females of H. cornigera; (2) the body is smooth in H. inermis and provided with large dorsal acute projections on pereonites 3 5 in H. cornigera; (3) the antenna 1 is clearly longer than half of the body in H. inermis and longer in H. cornigera; (4) the eyes are smaller in H. inermis than in H. cornigera; (5) the first pair of abdominal appendages is two-articulate in H. inermis and one-articulate in H. cornigera. The redescription of H. cornigera will be given by Takeuchi (in preparation) in the near future. The number of articles of antenna 2 varies among adult specimens of H. inermis n. sp., being either two or three, while in most of the genera of Caprellidea the number of articles is stable. The intraspecific variation indicates that the usage of

16 982 J. M. Guerra-García and I. Takeuchi number of articles in antenna 2 to differentiate species, or genera, should be considered in relation to ontogenetic development. Hircella inermis n. sp. has been found in very shallow waters, 3 5 m deep, clinging to the brown algae Sargassum vestitum and Acrocarpia paniculata and the red alga Plocamium angustum. Paraproto tasmaniensis new species (figures 9 14) Material examined. P48754: one male, two females, five juveniles; P48755: 15 juveniles; P48756: one male, one female, four juveniles; P48757: one female; P48758: six females; P48763: one female, one juvenile; P48764: one female, one juvenile; P48774: one female, one juvenile; P48777: one female; P48792: three juveniles; P48793: one female, four juveniles; P48799: two females, one juvenile; P48801: three juveniles; P48806: one female, two juveniles; P48807: one juvenile; P48813: one juvenile; P48814: one juvenile; TAS-151: two females, six juveniles; TAS-214: one juvenile; TAS-334: seven juveniles; TAS-348: one juvenile; TAS-349: three females, 24 juveniles. Etymology. The specific name indicates the place where the material was collected. Type material. Holotype male P48754 (AM P61281), collected from Armstrong Channel, Cape Barren Island by G. Edgar, 16 June 1992, 5 m deep. Allotype female P48806 (AM P61282) collected from Cemetery Bluff by I. Takeuchi and G. Edgar, 4 April 1996, clinging on the red alga Callophyllis lambertii, 5 m deep. Paratypes (AM P61283): two females, five juveniles P Type locality. Armstrong Channel, Cape Barren Island (40 30 S, E), Tasmania, Australia. Other records: Curtis Islands (39 28 S, E), Cape Portland (40 45 S, E), Judgement Rocks (39 31 S, E), Landing Beach, Hogan Island (39 13 S, E), Jacobs Boat Harbour (40 56 S, E), Green Bluff (42 44 S, E), Pointed Cliffs, Maria Island (42 44 S, E), Mercury Passage, Maria Island (42 34 S, E), Cemetery Bluff, Adventure Bay, Bruny Island (43 20 S, E), Sloop Reef, Bay of Fires (41 13 S, E), Scott Point, D Entrecasteaux Channel ( S, E) and Joes Bight, Freycinet Peninsula ( S, E), Tasmania, Australia. Description Holotype male Body length mm. Lateral view (figure 9A). Body dorsally smooth. Head rounded. Eyes small. Pereonite 1 fused with head, suture not present; pereonites 2 6 subequal in length; pereonite 7 the shortest. Gills (figure 9A). Present on pereonites 3 and 4, elongate, length about five times width. Mouthparts. Upper lip (figure 10B) symmetrically bilobed, smooth apically. Mandibles (figure 11A, B) with three-articulate palp; distal article of palp with setal formula 1-x-1, with x=9 in the left mandible and x=10 in the right; second article provided with five pairs of simple setae and one apical, 11 in total; mandibular molar absent; left mandible with incisor five-toothed, lacinia mobilis five-toothed followed by one large plate, smooth apically, a shorter robust plate provided with tiny distal denticules and a small hook, and a row of 11 setae; incisor of right

17 The Caprellidea from Tasmania 983 FIG. 9. Paraproto tasmaniensis new species. Lateral view. (A) Male; (B) female. Scale bar: 1 mm. mandible six-toothed, lacinia mobilis transformed into a smooth plate, followed by another smooth plate, a short robust plate with tiny denticules but without hook and a row of 11 setae; molar flake absent. Lower lip (figure 10C) with inner lobes clearly smaller than outer ones, well demarcated; inner and outer lobes provided with dense setulae on apical end; proximal projections of outer lobes well developed.

18 984 J. M. Guerra-García and I. Takeuchi FIG. 10. Paraproto tasmaniensis new species. Male. (A) Maxilliped; (B) upper lip; (C) lower lip; (D) maxilla 1; (E) maxilla 2. Scale bars: (A C) 0.3 mm; (D) 0.2 mm; (E) 0.1 mm. Maxilla 1 (figure 10D) outer lobe carrying six robust setae, serrate laterally; distal article of the palp with nine apical spine-like setae and a row of 10 setae medially. Maxilla 2 (figure 10E) inner lobe rectangular carrying 14 setae distally; outer lobe elongate, about 1.5 times as long as inner lobe, with 10 apical setae. Maxilliped (figure 10A) inner plate rectangular carrying three strong setae and two plumose

19 The Caprellidea from Tasmania 985 FIG. 11. Paraproto tasmaniensis new species. Male. (A) Left mandible; (B) right mandible. Scale bar: 0.3 mm. setae distally; outer plate, as large as the inner plate, with five distal setae and four medial setae; palp four-articulate, setose, dactylus with a row of setulae. Antennae. Antenna 1 (figure 12A) about two-thirds of body length; flagellum 20-articulate. Antenna 2 (figure 12B) a little shorter than half of antenna 1; swimming setae absent; flagellum seven-articulate. Gnathopods. Gnathopod 1 (figure 12C) basis as long as ischium, merus and carpus combined; merus and carpus setose and provided with a row of tiny setulae; propodus oval, length about 1.3 times width, palm with a row of minute setulae proximally, two pairs of proximal grasping spines and two rows of short spines along the palm; grasping margin of propodus palm and dactylus smooth. Gnathopod 2 (figure 12D) inserted on half of pereonite 2; basis 1.5 times as long as pereonite 2; ischium rectangular; merus rounded; carpus triangular; propodus elongate, about

20 986 J. M. Guerra-García and I. Takeuchi FIG. 12. Paraproto tasmaniensis new species. (A D) Male. (A) Antenna 1; (B) antenna 2; (C) gnathopod 1; (D) gnathopod 2. (E) Female gnathopod 2. Scale bars: 1 mm. 1.4 times as long as the basis; palm provided with three grasping spines medially and two rows of small ones along the palm on the distal half. Pereopods. Pereopods 3 and 4 (figures 13A, B) six-articulate; palm of carpus provided with four to five robust setae; palm of propodus with three robust setae proximally and a row of four to five shorter setae along the palm on the posterior

21 The Caprellidea from Tasmania 987 FIG. 13. Paraproto tasmaniensis new species. (A) Male pereopod 3; (B) male pereopod 4; (C) female pereopod 5; (D) male pereopod 6; (E) pereopod 7. Scale bar: 1 mm. half; dactylus setose. Pereopod 5 (figure 14C) small and setose; carpus carrying two robust setae on the palm; propodus rectangular carrying fine setae grouped densely on distal end; dactylus reduced and setose. Pereopods 6 and 7 missing in male

22 988 J. M. Guerra-García and I. Takeuchi FIG. 14. Paraproto tasmaniensis new species. (A) Male abdomen (ventral view); (B) male abdomen ( lateral view); (C) female abdomen (ventral view). Scale bar: 0.5 mm. holotype, described from the allotype female (figure 13D, E): palm of merus provided with a robust seta medially; carpus with robust setae (from proximal to distal end) on pereopod 6 and on the pereopod 7; palm of propodus with two pairs of grasping spines. Penes (figure 14A, B). Penes situated laterally, rounded, as long as wide. Abdomen (figure 14A, B). Abdomen with a plate (probably representing fused pleopods), two pairs of long two-articulate appendages (uropods) and a single dorsal lobe (figure 14B); distal article of the appendages about one-quarter as long as proximal one; second pair slightly shorter than the first pair. Allotype female Body length 9.8 mm. Flagellum of antenna 1 with 12 articles and flagellum of antenna 2 four-articulate (figure 9B). Carpus of gnathopod 2 shorter than in male (figure 12E). Oostegites not setose (figure 9B). Abdomen (figure 14C) without plate. Remarks The genus Paraproto, restricted so far to Australian waters and Antarctica, was composed of three species before this study: P. condylata ( Haswell, 1885) (without particular data on the type locality, but collected from Australia and Antarctica), P. gabrieli Stebbing, 1914 from Victoria and P. spinosa ( Haswell, 1885) from Victoria. Of the three species of Paraproto, P. tasmaniensis n. sp. is closest to P. condylata, especially in having the body smooth and in the general body feature. The type material of P. condylata described by Haswell (1885), Proto condylata, is missing (Springthorpe and Lowry, 1994) but a detailed redescription of P. condylata from Antarctica is included in Guerra-García and Coleman (2001). Paraproto tasmaniensis

23 The Caprellidea from Tasmania 989 differs from P. condylata as follows: (1) antenna 1 and pereonites 1 and 2 are elongate in P. condylata and robust in P. tasmaniensis; (2) the propodus of pereopods 3 and 4 are provided with only one medial spine in P. condylata while in P. tasmaniensis there is a row of seven to eight spines; (3) the propodus of pereopod 5 carries a group of setae distally in P. tasmaniensis while it is completely smooth in P. condylata; in general all pereopods are more setose in P. tasmaniensis than in P. condylata; (4) in connection with the mouthparts, the inner plate of the maxilliped carries three robust setae and two plumose setae in P. tasmaniensis while five strong setae are present in P. condylata; (5) the tiny appendages of the male abdomen present in P. condylata are lacking in P. tasmaniensis. Although P. tasmaniensis is one of the common species in Tasmanian waters, only two adult males have been found. Paraproto tasmaniensis n. sp. has been found clinging to brown algae (such as Acrocarpia paniculata, Perithalia caudata and Sargassum vestitum) and red algae (Plocamium angustum, P. dilatatum and Zonaria sp.) between 3 and 30 m deep. Paraproto spinosa ( Haswell, 1885) (figures 15 21) Proto spinosa Haswell, 1885: , pl. 49, figure 1. Paraproto spinosa: Mayer, 1903: 25, pl. 1, figures 8, 9, pl. 6, figures 16 19, pl. 9, figures 7, 54. Proto tuberculata Guiler, 1954: Phtisica tuberculata: McCain, 1968: 94. Material examined. P48754: one male, two females; P48758: seven males; P48768: five males, two females; TAS-180: one male; TAS-184: 15 males; TAS-334: one male. Redescription Male a P48768 (AM P61234) Body length mm. Lateral view (figure 15A). Pereonite 3 with a dorsal acute projection and two lateral ones. Pereonites 4 and 5 provided with a dorsal hump. Eyes large. Pereonite 1 fused with head, suture not present; pereonites 2 5 subequal in length; pereonite 6 about 1.5 times as long as pereonite 5; pereonite 7 the shortest. Gills (figure 15A). Present on pereonites 3 and 4, elongate, length about six times width. Mouthparts. Upper lip (figure 16B) symmetrically bilobed, smooth apically. Mandibles (figure 17A, B) with three-articulate palp; distal article of palp with setal formula 1-x-1, with x=10 in the left mandible and x=11 in the right; second article provided with five pairs of simple setae and one apical, 11 in total; mandibular molar absent; left mandible with incisor five-toothed, lacinia mobilis five-toothed followed by one large plate, a shorter robust plate provided with tiny distal denticles, and a row of nine setae; incisor of right mandible six-toothed, lacinia mobilis transformed as a plate, slightly denticulate, followed by another smooth plate, a short robust plate with tiny denticles and a row of 8 11 setae; molar flake absent. Lower lip (figure 16C) with inner and outer lobes provided with dense setulae; proximal projections of outer lobes well developed. Maxilla 1 (figure 16E) outer lobe carrying six robust setae, serrate laterally; distal article of the palp with seven apical spine-like setae and a row of nine setae medially. Maxilla 2 (figure 16D) inner lobe rectangular carrying 14 setae distally; outer lobe elongate, about 1.5 times as

24 990 J. M. Guerra-García and I. Takeuchi FIG. 15. Paraproto spinosa (Haswell, 1885). Lateral view. (A) Male; (B) female. Scale bar: 1 mm.

25 The Caprellidea from Tasmania 991 FIG. 16. Paraproto spinosa (Haswell, 1885). Male. (A) Maxilliped; (B) upper lip; (C) lower lip; (D) maxilla 2; (E) maxilla 1. Scale bars: 0.2 mm.

26 992 J. M. Guerra-García and I. Takeuchi FIG. 17. Paraproto spinosa (Haswell, 1885). Male. (A) Left mandible; (B) right mandible. Scale bar: 0.3 mm. long as inner lobe, with 10 apical setae. Maxilliped (figure 16A) inner plate rectangular carrying three strong setae and two plumose setae distally; outer plate as large as the inner plate; palp four-articulate, setose, dactylus with rows of setulae. Antennae. Antenna 1 (figure 18A) about two-thirds of body length; flagellum 17-articulate. Antenna 2 (figure 18B) longer than half of antenna 1; swimming setae absent; flagellum nine-articulate. Gnathopods. Gnathopod 1 (figure 18C) basis as long as ischium, merus and carpus combined; propodus oval, length about 1.3 times width, palm with a row of minute setulae proximally, two pairs of proximal grasping spines and two rows of short spines along the palm; grasping margin of propodus palm and dactylus smooth. Gnathopod 2 (figure 18E) inserted on the anterior part of pereonite 2; basis 1.5 times as long as pereonite 2; ischium rectangular; merus rounded; carpus triangular; propodus elongate, about 1.4 times as long as the basis; palm provided with three grasping spines medially and two rows of small ones along the palm on the distal half.

27 The Caprellidea from Tasmania 993 FIG. 18. Paraproto spinosa (Haswell, 1885). (A D) Male. (A) Antenna 1; (B) antenna 2; (C) gnathopod 1; (D) gnathopod 2. (E) female gnathopod 2. Scale bars: 1 mm. Pereopods. Pereopods 3 and 4 (figure 19A, B) six-articulate; palm of carpus provided with four to six robust setae; palm of propodus with three robust setae proximally and a row of shorter setae along the palm on the posterior half. Pereopod

28 994 J. M. Guerra-García and I. Takeuchi FIG. 19. Paraproto spinosa (Haswell, 1885). (A) Male pereopod 3; (B) male pereopod 4; (C) female pereopod 6; (D) female pereopod 7. Scale bar: 1 mm. 5 missing in all specimens. Pereopods 6 and 7 missing in male a, described from the female b (figure 19C, D): carpus with a group of three robust setae proximally followed by a row of three setae on pereopod 6 and only a row of three setae on pereopod 7; palm of propodus with two pairs of grasping spines. Penes (figure 20A). Penes situated laterally, rounded, as long as wide. Abdomen (figure 20A). Abdomen with a plate (probably representing fused pleopods), two pairs of long two-articulate appendages (uropods) and a single dorsal lobe; distal article of the appendages about one-quarter as long as proximal one; second pair slightly shorter than the first pair.

29 The Caprellidea from Tasmania 995 FIG. 20. Paraproto spinosa (Haswell, 1885). (A) Male abdomen (ventral view); (B) female abdomen (ventral view). Scale bar: 0.5 mm. Female b P48758 (AM P48758) Body length 12.1 mm. Flagellum of antenna 1 with 23 articles and flagellum of antenna 2 13-articulate (figure 15B). Carpus of gnathopod 2 shorter than in male. Oostegites not setose (figure 15B). Remarks Guiler (1954), in his description of Phtisica (=Proto) tuberculata from Tasmanian waters, stated that his species had gills on pereonites 3 and 4 and that the abdomen bore two pairs of rudimentary appendages. These characteristics were not consistent with the generic characteristics of Phtisica, and McCain (1968) pointed out that P. tuberculata should probably be transferred to Paraproto but did not implement this change because the type material of specimens described by Guiler (1954) was not consulted. The type material of P. tuberculata has been located in the Tasmanian Museum (holotype female G61, Mt Creek Gordon, 1954) (figure 21) and examined by the authors. Although it is a juvenile specimen in very poor condition, careful examination of the type material and materials from the Tasmanian coast revealed that Phtisica tuberculata of Guiler (1954) belongs to the genus Paraproto, being synonymous with Paraproto spinosa. The morphology of P. spinosa is very similar to P. tasmaniensis n. sp., but it can be easily distinguished by the presence of large projections on the dorsal surface of pereonites 3 5 which are lacking in P. tasmaniensis.

30 996 J. M. Guerra-García and I. Takeuchi FIG. 21. HOLOTYPE (JUVENILE) OF Phtisica tuberculata (Guiler, 1954) synonymized here with Paraproto spinosa. Scale bar: 1 mm. Family CAPRELLIDAE Leach, 1814 Caprella acanthogaster Mayer, 1890 (figures 22 26) Caprella acanthogaster Mayer, 1890: 80, pl. 7, figures 52, 53; Mayer, 1903: 78 79, pl. 3, figure 3. Material examined. P48785: three males, one female; P48791: many specimens; P48790: many specimens. Redescription Male a P48790 (AM P48790) Body length mm.

31 The Caprellidea from Tasmania 997 FIG. 22. Caprella acanthogaster Mayer, Lateral view. (A) Male; (B) female. Scale bar: 1 mm. Lateral view (figure 22A). Head and pereonite 1 smooth, suture present, pereonites 2 7 carrying small acute tubercles (figures 22A, 23A); pereonite 2 with two pairs of dorsal tubercles and one pair of lateral ones; pereonite 3 with five dorsal pairs and six lateral; pereonite 4 with seven dorsal pairs and four lateral; pereonite 5 with three dorsal pairs and three lateral; pereonites 6 and 7 with a pair of dorsal

32 998 J. M. Guerra-García and I. Takeuchi tubercles each. Pereonites 1 and 2 elongate; pereonites 3 5 subequal in length; pereonite 7 the shortest. Gills (figure 22A). Present on pereonites 3 and 4, elongate, length about seven times width. Mouthparts. Upper lip (figure 24B) symmetrically bilobed, setose apically. Mandibles (figure 24D, E) without palp; mandibular molar present; left mandible (figure E) with incisor five-toothed, lacinia mobilis five-toothed followed by three plumose setae; right mandible with incisor five-toothed, lacinia mobilis three-toothed followed by two plumose setae and a row of fine setulae; molar flake present on right mandible, rectangular, setose apically. Lower lip (figure 24C) with inner lobes well demarcated; inner and outer lobes provided with setulae on apical end. Maxilla 1 (figure 24F) outer lobe carrying seven robust setae and a small row of short setulae placed laterally; distal article of the palp with seven apical robust setae, five simple setae laterally and 11 setae medially. Maxilla 2 (figure 24G) inner lobe oval carrying 21 setae distally; outer lobe rectangular, about 1.3 times as long as inner lobe, with 15 apical setae. Maxilliped (figure 24A) inner plate rectangular carrying two strong short setae distally and several plumose setae; outer plate, as large as the inner plate, with three robust acute setae and a row of four robust blunt setae; palp four-articulate, setose, dactylus with rows of setulae. Antennae. Antenna 1 (figure 25A) about three-fifths of body length; flagellum 13-articulate. Antenna 2 (figure 25B) a little shorter than half of antenna 1; basal article of peduncle with a blunt projection apically; swimming setae present but not very well developed; flagellum two-articulate, basal article about four times as long as distal one. Gnathopods. Gnathopod 1 (figure 25C) basis as long as ischium, merus and carpus combined; ischium rectangular; merus and carpus setose; propodus elongate, length about twice width, palm with a pair of proximal grasping spines; grasping margin of propodus palm and dactylus minutely serrated. Gnathopod 2 (figure 25D) inserted on the posterior part of pereonite 2; basis a little shorter than pereonite 2 and provided with a carinate distal projection; ischium rectangular with a small projection distally; merus rounded; carpus triangular; propodus elongate, almost as long as the basis; palm provided with three projections, the proximal one carrying a grasping spine; dactylus hooked, with a row of small setae on proximal half. Pereopods. Pereopods 5 7 (figure 26A C) increasing in length; basis with a projection distally, palm of propodus with a pair of grasping spines proximally. Penes (figure 26E). Penes situated laterally, elontate, length about 1.8 times width. Abdomen (figure 26E). Abdomen with a pair of appendages, a pair of lateral lobes and a single dorsal lobe; appendages two-articulate; proximal article short carrying one seta, distal article about three times as long as proximal article, carrying four setae; lateral lobes setose. Female b P48791 (AM P48791) Body length 9.9 mm. Flagellum of antenna 1 15-articulate (figure 22B). Head and pereonite 1 provided with a pair of dorsal tubercles. Dorsal and lateral tubercles on pereonites 2 7 located as shown in figure 22B. Pereonites 1 and 2 not elongate. FIG. 23. Caprella acanthogaster Mayer, Dorsal view. (A) Male; (B) female. Scale bar: 1 mm.

33 The Caprellidea from Tasmania 999

34 1000 J. M. Guerra-García and I. Takeuchi FIG. 24. Caprella acanthogaster Mayer, Male. (A) Maxilliped; (B) upper lip; (C) lower lip; (D) right mandible; (E) left mandible; (F) maxilla 1; (G) maxilla 2. Scale bars: 0.2 mm.

35 The Caprellidea from Tasmania 1001 FIG. 25. Caprella acanthogaster Mayer, (A D) Male. (A) Antenna 1; (B) antenna 2; (C) gnathopod 1; (D) gnathopod 2. (E) female gnathopod 2. Scale bars: (A, B, D) 1 mm; (C, E) 0.5 mm. Gnathopod 2 inserted on the anterior part of pereonite 2; the projection of the basis of gnathopod 2 without the row of tiny teeth (carina). Carpus of gnathopod 2 twice as long as wide; two projections on the palm, the distal projection, present in male,

36 1002 J. M. Guerra-García and I. Takeuchi FIG. 26. Caprella acanthogaster Mayer, (A) Male pereopod 5; (B) male pereopod 6; (C) male pereopod 7; (D) female abdomen (ventral view); (E) male abdomen (ventral view). Scale bars: (A C) 1 mm; (D, E) 0.4 mm.

37 The Caprellidea from Tasmania 1003 is lacking in female. Oostegites not setose (figure 22B). Abdomen (figure 26D) without appengages; lateral lobes smooth. Remarks This uniquely large species of Caprella can be easily distinguished from the remaining Tasmanian caprellids by the presence of numerous dorsal tubercles along the pereonites. Features, such as large size of body, elongated pereonites 1 and 2, elongated basis of gnathopod 2, a pair of small tubercles on dorsal part of pereonite 2, numerous small projections on pereonites 2 5, assign the present species to C. acanthogaster Mayer, 1890, although the mature male from Tasmania lacks the small paired tubercles on the dorsal part of the head figured in previous studies (Mayer, 1903; Vassilenko, 1974; Takeuchi, 1995). Caprella acanthogaster has been recorded so far from China, the Russian Siberian coast of the Sea of Japan, Sakhalin Island and Japan (McCain and Steinberg, 1970; Arimoto, 1976; Takeuchi, 1995). In Tasmania the species has been recorded from Mercury Passage, Maria Island (see Edgar, 2000). Caprella acanthogaster has been found clinging to an exotic laminarian kelp Undaria pinnatifida ( Harvey) associated with buoys in areas of scallop aquaculture (present study) and to filamentous algae ( Edgar, 2000). Recently, U. pinnatifida and the large seastar Asterias amurensis (Lutken) were reported from the east coast of Tasmania as invasive species from the north-eastern Pacific (e.g. Sanderson, 1990; Byrne et al., 1997). In the case of A. amurensis, the transport from the northern Pacific to Tasmania is thought to have been as larvae in the ballast water of ocean-going vessels (Byrne et al., 1997). However, C. acanthogaster has the possibility of being an invasive species in Tasmania introduced with spat of scallop from the north-eastern Pacific. In general, Caprella spp. spend their whole life attached to the substratum surface due to lack of planktonic larval stages. Females keep their eggs within the broud pouch, and juveniles hatch directly from eggs, showing a miniature adult morphology. The morphology of Caprella spp. has been evolved to be well adapted for clinging to substrata such as algae and hydroids (see Caine, 1976; Takeuchi and Hirano, 1995; Aoki, 1999). In this decade, life histories of Caprella spp. have been described in detail based on laboratory experiments; C. danilevskii has a short generation length of 25.6 days at 20 C, which includes the incubation time of embryos and maturation time of hatched juveniles, and females produce eggs an average of 5.4 times after maturation ( Takeuchi and Hirano, 1991). The average life-span of C. danilevskii in the laboratory was 46.5 days for males and 46.0 days for females. Moreover, the distribution of C. acanthogaster in the north-eastern Pacific was restricted to cold temperate regions in the northern part of the Japanese Archipelago (Arimoto, 1976). Takeuchi et al. (2001) reported mass attachment of C. acanthogaster and C. mutica Schurin, 1935 on cultured scallop from Mutsu Bay, northern Japan. These features indicate the intolerance of C. acanthogaster for warmer equatorial waters, and hence, the possibility of introduction into Tasmanian waters by attaching to cultured scallop from the north Pacific, rather than by ballast waters. Further studies are necessary to elucidate the distribution mechanism of the exotic caprellid, C. acanthogaster. Caprella acanthopoda Guiler, 1954 (figure 27) Caprella acanthopoda Guiler, 1954: , figures 5, 6.